Abstract
We have measured Raman spectra of single crystals at room and low temperatures. We have determined all Raman-active modes. The results are in good agreement with the infrared results, but are inconsistent with a previous report of the Raman spectra [J. N. Gan et al., Phys. Rev. B 13, 3610 (1976)]. The effective charges are estimated from the longitudinal-transverse splitting of the optical-phonon modes. The temperature and pressure dependences of the mode are also presented.
- Received 31 October 1991
DOI:https://doi.org/10.1103/PhysRevB.45.13323
©1992 American Physical Society